Method, system, and apparatus for broadband and multi-frequency antennas for RFID devices formed by folding a planar structure

ABSTRACT

An RFID device is provided with a substrate and a plurality of RFID components associated to the substrate. The substrate is initially provided in a substantially planar configuration, with the RFID components being associated to the substantially planar substrate. After the RFID components have been associated to the substrate, the substrate is folded at at least one fold line to give the substrate and resulting RFID device a non-planar structure. All or portions of at least two of the RFID components are associated to portions of the substrate that are present in different planes, which may include portions of the substrate that are oriented in generally parallel planes or at an angle to each other. By such a non-planar, three-dimensional configuration, an RFID device may be provided with enhanced functionality, including increased bandwidth, ability to receive and radiate signals in a plurality of distinct frequency bands, and directivity.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority of U.S. ProvisionalPatent Application Ser. No. 62/724,950, filed Aug. 30, 2018, thecontents of which are incorporated by reference herein.

BACKGROUND Field of the Disclosure

The present subject matter relates to the manufacture of radio frequencyidentification (“RFID”) devices. More particularly, the present subjectmatter relates to the formation of non-planar, three-dimensional RFIDdevices by folding a planar structure.

Description of Related Art

RFID tags and labels (collectively referred to herein as “devices”) arewidely used to associate an object with an identification code. RFIDdevices generally have a combination of antennas and analog and/ordigital electronics, which may include, for example, communicationselectronics, data memory, and control logic. For example, RFID tags areused in conjunction with security locks in cars, for access control tobuildings, and for tracking inventory and parcels.

RFID devices are formed in a variety of manners. Typically, RFID devicesare formed with a substantially planar or flat structure. For example,RFID devices can be printed on or otherwise applied to a substrate anddeployed in a variety of environments, including adhering, coupling, orotherwise fastening the RFID device to an object or item. Depending onthe deployment, the RFID device may then be scanned or encoded withdesired data or information or provide data or information.

However, planar RFID devices and their associated components may havecertain limitations associated with bandwidth, use of multiple bands,and/or directivity.

SUMMARY

There are several aspects of the present subject matter which may beembodied separately or together in the devices and systems described andclaimed below. These aspects may be employed alone or in combinationwith other aspects of the subject matter described herein, and thedescription of these aspects together is not intended to preclude theuse of these aspects separately or the claiming of such aspectsseparately or in different combinations as may be set forth in theclaims appended hereto.

In one aspect or embodiment of the present disclosure, a method ofmanufacturing an RFID device includes providing a substantially planarsubstrate and associating a plurality of RFID components to thesubstrate. The substrate is folded at at least one fold line to define anon-planar RFID device

In a further aspect or embodiment of the present disclosure, an RFIDdevice includes a substrate, with a plurality of RFID componentsassociated to the substrate. The substrate is folded at at least onefold line to define a non-planar structure.

In an additional aspect or embodiment of the present disclosure, asystem for manufacturing an RFID device includes an application stationand a folding station. The application station is configured toassociate a plurality of RFID components to a substantially planarsubstrate. The folding station is configured to fold the substrate at atleast one fold line to define a non-planar RFID device.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of embodiments of the present disclosure will be apparentfrom the following detailed description of the exemplary embodimentsthereof, which description should be considered in conjunction with theaccompanying drawings in which like numerals indicate like elements, inwhich:

FIG. 1A shows an embodiment of an RFID device according to the presentdisclosure, in a pre-folding or initial condition;

FIG. 1B shows the RFID device of FIG. 1A in a post-folding or finalcondition;

FIG. 2A shows another embodiment of an RFID device according to thepresent disclosure, in a pre-folding or initial condition;

FIG. 2B shows the RFID device of FIG. 2A in a post-folding or finalcondition;

FIG. 3 shows yet another embodiment of an RFID device according to thepresent disclosure, in a pre-folding or initial condition;

FIG. 4 shows another embodiment of an RFID device according to thepresent disclosure, in a pre-folding or initial condition; and

FIG. 5A shows yet another embodiment of an RFID device according to thepresent disclosure, in a pre-folding or initial condition; and

FIGS. 5B and 5C show the RFID device of FIG. 5A in a post-folding orfinal condition.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Aspects of the present disclosure are disclosed in the followingdescription and related drawings directed to specific embodiments of thepresent disclosure. Alternate embodiments may be devised withoutdeparting from the spirit or the scope of the present disclosure.Additionally, well-known elements of exemplary embodiments of thepresent disclosure will not be described in detail or will be omitted soas not to obscure the relevant details of the present disclosure.Further, to facilitate an understanding of the description discussion ofseveral terms used herein follows.

As used herein, the word “exemplary” means “serving as an example,instance or illustration.” The embodiments described herein are notlimiting, but rather are exemplary only. It should be understood thatthe described embodiments are not necessarily to be construed aspreferred or advantageous over other embodiments. Moreover, the terms“embodiments of the present disclosure” and “embodiments” do not requirethat all embodiments within the scope of the present disclosure includethe discussed feature, advantage, or mode of operation.

According to an aspect of the present disclosure, and referringgenerally to the Figures, three-dimensional or non-planar RFID devicesand methods of forming such devices, will be shown and described. Such athree-dimensional RFID device may have several advantages over aconventional RFID device, which is substantially flat or planar ortwo-dimensional. For example, a three-dimensional, non-planar RFIDdevice according to the present disclosure may be provided with asecondary element that extends the bandwidth of the RFID device, whichmay include extending the bandwidth of a patch antenna from about 10% toabout 20% of the operational frequency. Additionally (or alternatively),a three-dimensional, non-planar RFID device according to the presentdisclosure may be operable over multiple bands of frequencies, receivingand radiating signals in the range of 800 MHz to 1000 MHz, 2400 MHz to2500 MHz, and 5.6 GHz to 6 GHz, for example. Additionally (oralternatively), a three-dimensional, non-planar RFID device according tothe present disclosure may be provided with directivity, with maximumgain being pointed in a defined direction. Indeed, three-dimensional,non-planar RFID devices according to the present disclosure may haveimproved effectiveness and performance compared to traditional, flatRFID devices.

Referring now to FIGS. 1A and 1B, an exemplary three-dimensional ornon-planar RFID device and method of forming the same are shown, withFIG. 1A showing the RFID device in an initial or pre-folding condition(generally identified at 100) and FIG. 1B showing the RFID device in apost-folding or final condition (generally identified at 111). The RFIDdevice includes a substrate 102 with a plurality of RFID componentsassociated thereto. The RFID components may be associated to thesubstrate 102 according to any suitable approach, which may depend uponthe nature of the individual RFID component. For example, it may beappropriate for certain RFID components to be printed onto the substrate102, while it may be appropriate for other RFID components to be crimpedto the substrate 102. It is also within the scope of the presentdisclosure for an RFID component to not physically contact the substrate102, but to instead be associated to the substrate 102 by an adhesivelayer (or the like) or by being mounted onto another RFID component thatis secured to the substrate 102, for example.

The substrate 102 of the RFID device is initially disposed in asubstantially flat or planar or two-dimensional orientation (as shown inFIG. 1A). The substrate 102 may be formed from any suitablenon-conductive material that is (or may be processed or treated to be)susceptible to folding, such as paper or polyethylene terephthalate(“PET”). The substrate 102 includes at least one defined separation orfold line 104, 106. In the embodiment of FIG. 1A, two substantiallyparallel fold lines 104 and 106 are shown, but it should be understoodthat there may be a different number of fold lines (including only onefold line or more than two fold lines) and that a fold line may bevariously configured (e.g., curved or otherwise non-linear) withoutdeparting from the scope of the present disclosure.

The fold line 104, 106 may be visually and structurallyindistinguishable from the other regions of the substrate 102,representing a location at which the substrate 102 is to be folded (aswill be described in greater detail herein). However, in otherembodiments, the fold line 104, 106 may be visually and/or structurallydistinct from other regions of the substrate 102. For example, the foldline 104, 106 may be differently colored than another region of thesubstrate 102, such as being marked by a colored ink or the like. Inanother embodiment, the fold line 104, 106 may be scored or narrowed orotherwise weakened compared to other regions of the substrate 102,making it more susceptible to folding (as will be described in greaterdetail herein).

A layer 108 of foam or other dielectric material (or spacer) may beassociated to one side of substrate 102, opposite to the RFIDcomponents. As with the substrate 102, it may be advantageous for thelayer 108 to be susceptible to folding or deformation, at least in theregions aligned with the fold line(s) 104, 106 of the substrate 102.

Turning now to the RFID components, they may be variously configuredwithout departing from the scope of the present disclosure. Generallyspeaking, the term “RFID components” refers to an RFID chip 110 and thefunctional elements of the RFID device that are formed of a conductivematerial (e.g., aluminum). This may include, without limitation, a driveelement or radiating element 112 (e.g., a slot antenna or patchantenna), a director 114, a reflector 116, a ground plane, andconductive leads or traces or interconnects between two or more RFIDcomponents.

As described above, the RFID components may be associated to thesubstrate 102 using any suitable approach. Additionally, the RFIDcomponents may be positioned on the substrate 102 in any orientation. Inthe configuration of FIGS. 1A and 1B, the RFID components 110, 112, 114,and 116 are oriented so as to not cross any of the fold lines 104, 106.In other embodiments, which will be described herein, at least one RFIDcomponent may cross a fold line.

With the RFID components associated to the substrate 102, the substrate102 is folded at the fold line(s) 104, 106 to move it from its initial,planar configuration 100 (FIG. 1A) to its folded or three-dimensional ornon-planar configuration 111 (FIG. 1B). FIGS. 1A and 1B show thesubstrate 102 being folded into a stack having a plurality of (namelythree) generally parallel substrate layers, but it should be understoodthat a stack may have two generally parallel substrate layers or morethan three generally parallel substrate layers. Providing an RFID devicewith RFID components associated with more than three generally parallelsubstrate layers of a stack may increase bandwidth and/or addoperational frequencies to the RFID device, for example. Additionally,other (non-stacked) folded configurations may be employed withoutdeparting from the scope of the present disclosure, as will be describedin greater detail herein.

The folded configuration 111 of FIG. 1B provides for defined separationsbetween the director 114, the antenna or drive (or radiating) element112, and the reflector 116, with each RFID component being located in adifferent plane and associated to a different layer of the stack. Theseparation between the RFID components may be important to properoperation of the RFID device and be affected by the thickness of thespacer or dielectric layer 108, such that it may be advantageous toemploy a spacer or dielectric layer 108 having an appropriate thickness.The folded orientation 111 of FIG. 1B may allow for the direction ofmaximum gain in a direction along the axis of the RFID device, in adirection from the reflector 116 toward the director 114, though itshould be understand that other advantages may be realized withdifferently configured RFID components.

In one embodiment, the substrate 102 is folded in such a way that itwill not tend to deform from the folded configuration 111 to the flatconfiguration 100. However, if the substrate 102 has a tendency todeform from the folded configuration 111 to the flat configuration 100,it may be advantageous to provide a locking mechanism to retain thesubstrate 102 in the folded configuration 111. The nature of the lockingmechanism may vary without departing from the scope of the presentdisclosure, but it is preferably selected so as to not interfere withproper operation of the RFID device. In one exemplary embodiment, thelocking mechanism may be an adhesive that secures one substrate layer toan adjacent substrate layer. In another exemplary embodiment, thelocking mechanism may be a clip or wrap or retainer that entraps thesubstrate 102 to prevent it from moving away from its foldedconfiguration 111. It is also within the scope of the present disclosurefor a plurality of similarly or differently configured lockingmechanisms to be incorporated into a single RFID device.

Referring now to FIGS. 2A and 2B, a variation of the RFID device ofFIGS. 1A and 1B is shown. In the exemplary embodiment of FIGS. 2A and2B, the director 114 is replaced by a second drive or radiating element118. The drive elements 112 and 118 are connected by an interconnect orconductive lead or trace 120. In contrast to the RFID components ofFIGS. 1A and 1B, the interconnect 120 is an RFID component that extendsacross one of the fold lines 104. Thus, when the substrate 102 is movedfrom its flat configuration 200 (FIG. 2A) to its folded configuration211 (FIG. 2B), the interconnect 120 is similarly folded, effectivelycoupling the RFID chip 110 to drive elements 112 and 118 in differentplanes.

Due to the interconnect 120 being folded when moving the substrate 102from its flat configuration 200 to its folded configuration 211, it maybe advantageous for the interconnect 120 (or any other RFID componentthat extends across a fold line) to be configured to be folded, which isshown in FIG. 2B as the interconnect 120 being relatively thin comparedto the other RFID components, rendering it more susceptible to beingfolded. While FIG. 2B shows the interconnect 120 as being relativelythin, it should be understood that an RFID component extending across afold line may be otherwise configured to render it more susceptible tobeing folded (e.g., by forming it of a more flexible material than thematerial used to form other RFID components). It should also beunderstood that an RFID component extending across a fold line is notlimited to an interconnect between two drive elements (as in FIGS. 2Aand 2B), but may be some other RFID component.

FIG. 3 illustrates another embodiment of a three-dimensional RFID deviceaccording to the present disclosure. While FIG. 3 shows the RFID devicein a flat or planar configuration 300, it should be understood that itis configured to be folded at one or more fold lines in order to definea non-planar, three-dimensional structure, such as the structures ofFIGS. 1B and 2B. In the embodiment of FIG. 3, the RFID device includes aplurality of RFID components associated to a substrate 102 such that,when the substrate 102 is folded at fold lines 104 and 106, a patchantenna is formed. More particularly, the patch antenna may be formedfrom a half wave patch such that the length of edges of a driven patch122 equal one half wavelength in the dielectric environment present. Aconductor or interconnect 120 extends across a fold line 106, connectingthe RFID chip 110 (around a fold, as in FIG. 2A) to a ground plane 124.A secondary or parasitic patch antenna 126 is spaced from the main patchantenna 122 by a fold line 104 and configured to be positioned in frontof the main patch antenna 122 when the RFID device is in its foldedconfiguration. This orientation of the driven patch antenna 122 and thesecondary patch antenna 126 can provide for extended bandwidth of theRFID device and/or provide multi-frequency capabilities and operation.

FIG. 4 illustrates another embodiment of an RFID device according to anaspect of the present disclosure. While FIG. 4 shows the RFID device ina flat or planar configuration 400, it should be understood that it isconfigured to be folded at one or more fold lines in order to define anon-planar, three-dimensional structure, such as the structures of FIGS.1B and 2B. In the embodiment of FIG. 4, a pair of drive elements areconfigured as a dipole-form antenna 112 with a reflector and a coilantenna 128 (for example an HF coil antenna) designed to operate in theregion of 13.56 MHz. When this RFID device is folded at the fold lines104 and 106, the distance between the ground plane 124 and the coilantenna 128 can be increased, which can result in a correspondingincrease in the efficiency of the coil antenna 128 through a reductionin eddy current loss.

As noted above, RFID devices according to the present disclosure are notlimited to any particular folded configuration (e.g., the stackedconfiguration of FIGS. 1B and 2B), but may be folded into any of avariety of three-dimensional, non-planar configurations. For example,FIG. 5A illustrates an RFID device in a flat or planar configuration500. The RFID device is folded at fold lines 104 and 106 to define athree-dimensional or non-planar structure, as in the precedingembodiments. However, rather than the substrate 102 being folded so asto define a stack with generally parallel substrate surfaces (as inFIGS. 1B and 2B), the substrate 102 is instead folded to orient at leastone substrate surface (having at least one RFID component associatedthereto) at an angle with respect to another substrate surface (havingat least one other RFID component associated thereto).

FIGS. 5B and 5C illustrate one possible implementation of this approach,with the substrate 102 being folded at two fold lines 104 and 106 toprovide an RFID device having a closed, generally prismaticconfiguration 502 having a generally triangular cross sectional shape.While FIGS. 5B and 5C show the RFID device with a generally triangularprofile, it should be understood that an RFID device according to thepresent disclosure may be folded into any other three-dimensional shape,such as a cube or cylinder. In such embodiments, larger separationsbetween the antenna elements 112 and 118 and the ground plane 124 may berealized than what may be possible with a foam spacer (as in theembodiment of FIGS. 1A and 1B). Additionally, a closed, generallyprismatic configuration in which the RFID components are positionedinwardly of the substrate 102 (as in FIGS. 5B and 5C) may beadvantageous to shield the RFID components from the outside environment(using the substrate 102). As in other exemplary embodiments, suchelements and folding may be varied to provide enhanced RFIDcapabilities.

RFID devices according to the present disclosure may be manufacturedusing any suitable system. In an exemplary embodiment, a system includesan application station configured to associate the various RFIDcomponents to the substrate, which may include a layer of conductivematerial being formed onto the substrate, followed by the conductivematerial being processed (e.g., being stripped from the substrate or cutusing a laser or die) to define one or more of the RFID components. Inanother embodiment, conductive material may be printed onto thesubstrate to define one or more RFID components. An RFID chip may beelectrically coupled to one or more of the other RFID components afterall or some of the other RFID components have been associated to thesubstrate.

In addition to the application station, the exemplary system furtherincludes a folding station configured to fold the substrate at at leastone fold line to define a three-dimensional, non-planar RFID device. Thenature and configuration of the folding station may vary, depending onthe nature of the fold(s) to be imparted to the substrate.

In one embodiment, the substrate may comprise a web of material, withthe RFID components of a plurality of RFID devices being associated tothe same web of material. In this case, the system may further include aseparation station for separating the RFID devices of a web of materialfrom each other (e.g., by cutting the web with a blade or the like).Such a system may be configured to separate the RFID devices beforefolding any of the devices or may instead be configured to fold some orall of the devices before separating them.

The foregoing description and accompanying figures illustrate theprinciples, preferred embodiments and modes of operation of theinvention. However, the invention should not be construed as beinglimited to the particular embodiments discussed above. Additionalvariations of the embodiments discussed above will be appreciated bythose skilled in the art (for example, features associated with certainconfigurations of the invention may instead be associated with any otherconfigurations of the invention, as desired). Therefore, theabove-described embodiments should be regarded as illustrative ratherthan restrictive. Accordingly, it should be appreciated that variationsto those embodiments can be made by those skilled in the art withoutdeparting from the scope of the invention as defined by the followingclaims.

The invention claimed is:
 1. A method of manufacturing an RFID device,comprising: providing a substantially planar substrate; associating aplurality of RFID components to the substrate; and folding the substrateat at least one fold line to define a non-planar RFID device, whereinsaid non-planar RFID device includes a plurality of generally parallelsubstrate layers, and at least two of the RFID components are associatedto different substrate layers, and wherein said folding the substrate atthe at least one fold line to define a non-planar RFID device includingfolding the substrate at a plurality of fold lines to define an RFIDdevice having at least three generally parallel substrate layers.
 2. Themethod of claim 1, wherein none of the RFID components extends acrosssaid at least one fold line.
 3. The method of claim 1, wherein at leastone of the RFID components extends across said at least one fold line.4. The method of claim 1, wherein said non-planar RFID device includes afirst substrate surface oriented at an angle with respect to a secondsubstrate surface, at least one of the RFID components is associated tothe first substrate surface, and at least one of the RFID components isassociated to the second substrate surface.
 5. The method of claim 4,wherein said folding the substrate at at least one fold line to define anon-planar RFID device includes folding the substrate at a plurality offold lines to define an RFID device having a closed, generally prismaticconfiguration.
 6. An RFID device, comprising: a substrate; and aplurality of RFID components associated to the substrate, wherein thesubstrate is folded at at least one fold line to define a non-planarstructure, wherein said non-planar structure includes a first substratesurface oriented at an angle with respect to a second substrate surface,at least one of the RFID components is associated to the first substratesurface, and at least one of the RFID components is associated to thesecond substrate surface, and wherein said non-planar structure has aclosed, generally prismatic configuration.
 7. The RFID device of claim6, wherein none of the RFID components extends across said at least onefold line.
 8. The RFID device of claim 6, wherein at least one of theRFID components extends across said at least one fold line.
 9. The RFIDdevice of claim 6, comprising a plurality of generally parallelsubstrate layers, wherein at least two of the RFID components areassociated to different substrate layers.
 10. The RFID device of claim9, comprising at least three generally parallel substrate layers.